MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - misfire under medium to heavy acceleration

i seem to have developed quite a bad a misfire under medium to heavy acceleration, is this due to plugs /leads? or is there another cause. 1996 VVC 80K

if it is the plugs and /or leads which make should i invest in?
richb

Plugs and/or Leads ?
Almost certainly.

Plugs should have been replaced at the 5 year / 60K service; check that you have the long life ones fitted, or replace them (plenty of advice on plug types in archive).

If your HT leads have not been changed then this is a relatively simple job. B&G sell some suitable leads (you don't need the 'racing' variant though).


Steve
Steve

Use the 8mm magnecor leads that B&G retail as Steve rightly suggests Rich, the blue ones.

Pretty simple replacement (http://www.mgf.ultimatemg.com/replace_sparkplugs.htm)

HTH
Rob Bell

And you might try doing the rotor arm and cap at the same time. - oops not on a VVC!
the problem is it is more difficult to generate a spark in high pressures, when you open the throttle more air gets into the engine, thus higher pressures, so no spark.
It is possible that it is due to damaged coils, they are badly positioned to catch rainfall in the VVC.
Will Munns

Rich

A word of advice, get it sorted ASAP as I found out the consequences of misfiring with a catalyst fitted 3 weeks ago in similar circumstances.

My HT leads went on the VVC and caused a misfire, which meant unburnt fuel got ejected via the exhaust and on entering the Cat burnt!.Bang (fuel exploding)- This breaks the ceramic inside of the cat, which means a new cat.

This happened very quickly - I noticed the car losing power approx 1 mile to work. Drove the car to the garage (2miles) from work, by which time I noticed a rattle from the exhaust. This turned out to be the cat. IMHO I would get it sorted immediately otherwise your outlay on HT leads or plugs could very quickly escalate into £2-300 for a new cat as well.

I was lucky the garage paid half (still in MGR warranty), but don't risk it, get it checked ASAP.

Cheers

DJ

DJ

cheers chaps, leads on order pick plugs up at the weekend, i am a bit worried about DJ's comments, it could be to late for may cat. oh well time for the cat by pass kit....
richb

Rich

Don't panic, if it ain't rattling you are OK, but it is something to be aware of. Probably a good idea not to try booting it as that may end up just pushing more fuel through and out the exhaust.

Take it easy

DJ


DJ

This thread was discussed on 21/08/2002

MG MGF Technical index

This thread is from the archive. The Live MG MGF Technical BBS is active now.